Partner Sites:  www.BOEmarine.com | www.CBangler.com | www.BandofBoaters.com

Results 1 to 6 of 6
  1. #1
    Join Date
    Nov 2016
    Location
    Ottawa canada
    Boat
    Sea ray Sundancer
    Details
    260 Sea Ray Sundancer
    Engine(s)
    5.7L
    Posts
    2

    Opinion on Compression

    I have a 1985 Sea Ray 260 it has a 5.7 liter engine. I have just run a compression test and have the following results:
    DRY WET
    1) 142 209
    2) 126 205
    3) 180 224
    4) 185 215
    5) 125 170
    6) 105 160
    7) 185 208
    8) 120 180

    Should I be concerned or replace the rings? Suggestions and opinions welcome.

  2. #2
    Join Date
    Aug 2011
    Location
    cape cod mass
    Boat
    sea ray
    Details
    2006 sea ray 280
    Engine(s)
    Twin 5.0's with B3's closed cooling with Kohler 5E
    Posts
    1,584

    Re: Opinion on Compression

    I'd be concerned. How's it run ? How much oil does it use ? Can you live with it ? I'd pull that out in a heart beat if it was mine, but that's me.

  3. #3
    Join Date
    Oct 2006
    Location
    Middle Tennessee/NW Florida
    Boat
    Sea Ray & a 22 Boston Whaler Dauntless 225 Merc - (now sold)
    Details
    1996 450DA
    Engine(s)
    3116 Caterpillars
    Posts
    9,972

    Re: Opinion on Compression

    We see this a lot on the Gulf coast where boats have been stored over the winter. When not running, several intake and exhaust valves are open and sometimes surface rust forms on the valve face. Before I did anything or spent any money, I'd run the boat for several hours at a decent or planing speed and then retest the compression. You might be lucky and find that the valves clean up and the problem will go away.
    Frank

  4. #4
    Join Date
    Feb 2008
    Location
    Stamford CT "Ponus Yacht Club"
    Boat
    Searay
    Details
    1995 400EC. Raymarine E80,4kw dome, Garmin 235 gps, 11ft Baltik / 15hp on St croix davits.
    Engine(s)
    2013 7.4L Mercruiser Blue water. Hurth straight shaft 630's, Westerbeke 7.0 BCG
    Posts
    2,020

    Re: Opinion on Compression

    From experience, I completely agree with Frank.
    Those numbers are currently not acceptable!


    Boats that aren't run often, are subject to rusty valves that affect sealing and therefore compression. This is why we here in the North fog our GAS engines with oil during winter lay-up (Diesel engines are already full of oil).
    It's rarely the bottom of the engine that's the problem, piston/rings ect.
    A top end job is a common procedure.
    Mark.

  5. #5
    Join Date
    Aug 2011
    Location
    cape cod mass
    Boat
    sea ray
    Details
    2006 sea ray 280
    Engine(s)
    Twin 5.0's with B3's closed cooling with Kohler 5E
    Posts
    1,584

    Re: Opinion on Compression

    The wet test has been used as a benchmark to check ring condition. It would be unreasonable to think the oil came up off the piston and sealed both intake and exhaust valves to the degree that was observed in his wet/ dry results.

    Totally agree with running it and retesting. Leak down test would give more insight to where the lost compression is going

  6. #6
    Join Date
    Aug 2010
    Location
    New Jersey
    Boat
    in between
    Details
    Ex SRV 240 Weekender twin
    Engine(s)
    in between
    Posts
    2,310

    Re: Opinion on Compression

    Those reading are do not correspond to a 32 year old engine. see post 4

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •